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12v vs. 24v cummins. Lets debate

19K views 27 replies 14 participants last post by  turbo daddy 
#1 ·
The next diesel truck i wanna buy will be a cummins, 94-02. Ive started doing some light research between the 2 engines, but lets assume i know nothing more on these other then 12v is mechincal and 24v has electronics.

The purpose of this truck will be a play toy, looking to make big, big power.
 
#2 ·
i have a 95 12 valve, and my buddy has a 2000 24v, the main difference
between the 2 is that mine is way cheaper to hotrod, the bosch p7100
injection pump is the holley carburetor of the diesel world. U can make
a ton of adjustments which means big power for cheap. i prefer the
12v.
 
#3 · (Edited)
I have a 99 24v my first cummins truck and love it. The 24V is sweet because you can make a big increase in power by just by getting a programmer which displays everything you want to know on one screen instead of 5 extra gauges on your dash, but if you want to make real big power and get your hands a little dirty the 12v is the way to go.
 
#6 ·
if you want it to make big power then hands down go with a 12 valve. if you want easy power but not as much then go with a 24v because it is basicly just all plug and play. if you reliablility and big power again 12v. there is alot more you can do with a 12v for nothing or next to nothing to make big power. lets see thats 3 points for 12v and 1 for 24v. it really depends on how much power you want and how easy you want it. if you dont like gettin your hands dirty and just plugin stuff in or if you dont mind wrenchin a little.
 
#7 ·
Go over to dtr and start seeing who you agree with more, the 12v or 24v guys.

I will run 12 valves as long as I can just because they are simple and pretty close to bulletproof. I have my 3rd >200,000 mile truck right now, and my cousins truck just rolled 300,000 and still rolls alot of coal.

Also, no pump problems is a big deal. An injection pump can cost as much as a gas motor.
 
#8 ·
yep, ive heard about the problems with the VF44, would like to stay away from that. Id love to just ramp up my Powerstroke but cost vs. power output isnt anywhere close to a Cummins or Duramax. Granted black widow compounds would be cool but the required hardware to do so is more then 2x the cost to do it on a 12v Cummins.
 
#10 ·
why not a 04.5-06,7? higher stock hp and tq, quieter motor, easy cheap big power.

I know there are more electronics, but they are still wicked easy to work on.....I love my 04 and a half :nana:

i just have a FASS and an edge EZ right now, and have quite a few buddies comment on how fast it is, and one with a powerstroke that wont even think about lining up with me....his excuse is "I dont wanna make you cry":teehee: 01 stock powerstroke FTW!
 
#26 ·
People shy away from the electronics like they are some kind of plague, kind of like how the hard cores still run carbs on the gassers when fuel injection is so much more efficient.

I'm not knocking the 12v, it's a great engine and for less than 100$, you can make some great power and smoke. The only downfall I see is that you may have some hard luck trying to find a 12v in the MI area with a clean body. If your willing to travel to get yours or have it shipped, you may have better luck. Whichever you decide, stay with the Cummins!
 
#11 ·
i currently have a 12v that has 400,000 miles and is still goin strong. its nothin to have a 12v with at least 1/2 mill. on the odometer and still runnin. not sayin that the 24v dont run that long its just more common for 12v. i mean look at the pullin league also. how many 12v do you see in there vs. 24v. if you are looking for shear power ability nothin will ever beat a 12v.
 
#12 ·
12v absolutely no doubt about it.

i have dealt with plenty of these rigs, and there is a reason that i roll with 12v's.

the ONLY real advantage to a 24V is that you can adjust your power level from inside the cab. this advantage is only reasonably valid anyway, as any programmer that is worth buying for a performance gain is a downloader, where you will be sitting on the side of the road or a parking lot for 5-10 minutes while the downloader downloads. it takes the same amount of time to adjust or swap a fuel plate. while there are the adjustable on the fly units, they just dont make any power, so they have to be piggybacked with a downloader.

advantages to a 12V

simpler
every performance mod is cheaper
better fuel milage
better drivability (12v's have a much easier to use power curve than the 24v, which is like a 125 two stroke.)
power delivery is easier on driveline components
far superior injection pump, both from a performance and reliability standpoint
far superior lift pump (they dont go bad every 70k)
auxillary fuel system not required
injectors are accesible without removing valve cover
already has the stronger hydraulics needed for stout clutches
not cluttered with electric sensors to fail
the newer truck ammenities are a bolt on/in deal
did i mention its cheaper and easier to do everything, while getting better fuel milage?

24V advantages
very mild power gains adjustable in cab.
cruise control warm-up
available with the nicer sport front end
available with a stock six speed
available with stock rear disk brakes
if your wallet is heavy, this will lighten it up real quick, since there are way more parts needed for similar power levels.

FWIW, i have about $2500-3000 total into the 12V in my 98, which nets me around 500-600 hp.
my best friend had about $4500-5500 into his 01 24V, to make similar power, but a little bit shy of mine.

my pops has a 99 24V, and i gave him an edge juice with attitude for x-mas a couple years ago. its a little dissapointing that my 312,xxx mile '96 12v with only free mods will blow his truck away, in all aspects, including towing.
 
#13 ·
Lots of people talk about the ability to "adjust" the power. A valet switch can be used to do this on a 12 valve. If I remember correctly it blocks/restricts the afc unit from allowing full fuel.

Need any more reason to go 12 valve?
 
#17 ·
I have a 12v with compounds, studs, o-rings, Helix-2 cam, springs, etc. twin disk clutch, billet input, Spearco intercooler, fluidampr, tuned injeciton pump, blah blah, it'll run faster than my friend's '97 'Vette.

Get a 12 valve if you want it to live under power. The VP44 will die on you, they really can't be made to fuel hard up to 4k, and even at that high of rpm, you need very epxpensive valvesprings to make that 24valve live up there.

I don't know exactly how high mine will rev, because the tach stops at 4k, and my multimeter won't keep a record of peak rpm. Anyway, the one major disadvantage I see about the 12v is that the injection timing is fixed. I don't really like this. Mine is set at 23 degrees, which makes it gutless down low, but kick you in the ass at about 2500 rpm. If it had a timing curve, like is do-able in the newer trucks it could pull hard all the way up.

I'm planning to back the timing off a little pretty soon, as I don't spend a ton if time up in the revs anyway.

My next truck will most likely be a Common Rail, and it won't be hot rodded too much.
I have about 200k on mine with daily trips to 4000 rpm and 60psi of boost.
Runs like a top, but I need more crankcase ventilation . . . at that high of engine output there are a lot of gases that need to be vented, and I'm leaking from everywhere now. My driveway hates me, lol.
 
#18 ·
Also,
If you're wanting big power, find a '97-'98 with a 5 speed. They come with the 215hp injection pump and a Dana 80 rear. You'll need a new clutch after about $9 worth of mods. :)
I hate the 5 speed, but I don't have $10k to build an auto either.
 
#20 ·
actually its the '96s also, so 96-98 with a five speed. i love the five speed, but am putting six speeds in both of mine, for strength purposes. i wish i could have a nv4500 with the strength of G56 gears and a NV5600's case.

i cant stand driving auto's. the only time i wish i had an auto is if i am eating a burger while driving through a side wind upon acceleration. and in that instance, i wish i had a third arm more than an auto trans.

keep in mind that your going to want a dual disk clutch, so get one right off the bat. dont waste your time with a POS single.
 
#19 ·
i personally would say go with a manual no matter what if you plan on makin power or have about $5000 to build the tranny right. i.e. billet shafts, good clutches, valve body, convertor...... with a manual you just upgrade the clutch once and call it good. unless you have really bad knee problems that would hinder you from driving a manual atleast.
 
#22 ·
I have owned 4 12v Trucks and 2 24v trucks, one being the HO 6 speed version. I now have the 12v. The 24 valve is not reliable, both of mine had injection pump issues at low miles. My current 12v has almost 200k on it and runs like new. My 12v also gets better mileage.
 
#24 ·
I'm gonna go hail mine in a few minutes.

It's never failed me yet, 200k on her.
4000rpm @ 60psi boost every day. :)
 
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